{"gene":"ASXL2","run_date":"2026-04-28T17:12:37","timeline":{"discoveries":[{"year":2015,"finding":"BAP1 forms two mutually exclusive complexes with ASXL1 and ASXL2; ASXL2 uses its ASXM domain to interact with the C-terminal domain (CTD) of BAP1, and this interaction is required for ubiquitin binding and H2A deubiquitination. BAP1 is essential for maintaining ASXL2 protein stability (but not ASXL1), and cancer-associated loss of BAP1 results in ASXL2 destabilization. The ASXM-CTD interaction generates a composite ubiquitin-binding interface (CUBI) that engages multiple contacts with ubiquitin to promote H2A Lys-119 deubiquitination. BAP1/ASXL2 interaction also regulates cell senescence.","method":"Co-immunoprecipitation, in vitro deubiquitination assays, active-site and domain mutagenesis (including cancer-associated mutations), cell proliferation and senescence assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 — reconstituted DUB activity in vitro, reciprocal co-IP, domain mutagenesis, multiple orthogonal functional assays","pmids":["26416890"],"is_preprint":false},{"year":2022,"finding":"ASXL2 (as a subunit of the BAP1 complex) mediates a direct interaction with MLL3/COMPASS, recruiting it to enhancers of tumor suppressor genes. ASXL2 loss results in decreased MLL3 occupancy at enhancers and reduced BAP1-MLL3 target gene expression. PRMT4/CARM1 methylates ASXL2 at R639/R641, which blocks ASXL2 binding to MLL3 and impairs MLL3/COMPASS-dependent gene expression.","method":"Co-immunoprecipitation, ChIP-seq, loss-of-function (ASXL2 knockdown/knockout), in vitro methylation assay, site-directed mutagenesis of methylation sites","journal":"Science advances","confidence":"High","confidence_rationale":"Tier 1-2 — direct interaction demonstrated by co-IP, PTM writer identified with mutagenesis, ChIP-seq for genomic occupancy, multiple orthogonal methods","pmids":["36197977"],"is_preprint":false},{"year":2015,"finding":"ASXL2 interacts with PPARγ and regulates osteoclast differentiation via two distinct pathways: (1) a PPARγ/c-Fos-dependent pathway for osteoclast formation, and (2) a PGC-1β-dependent but c-Fos-independent pathway for osteoclast mitochondrial biogenesis. ASXL2-/- mice are insulin resistant, lipodystrophic, and severely osteopetrotic due to failed osteoclast differentiation.","method":"Genetic knockout mouse model (ASXL2-/-), genetic epistasis (c-Fos, PGC-1β pathway analysis), co-immunoprecipitation with PPARγ, osteoclast differentiation assays","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 — knockout mouse with defined phenotypic readouts, genetic epistasis placing ASXL2 in PPARγ/c-Fos and PGC-1β pathways, co-IP for PPARγ interaction","pmids":["26051940"],"is_preprint":false},{"year":2015,"finding":"ASXL2 interacts with ligand-bound ERα and forms a complex with histone methylation modifiers LSD1, UTX, and MLL2, which are recruited to E2-responsive gene promoters via ASXL2. The PHD finger of ASXL2 preferentially binds dimethylated H3K4. ASXL2 depletion reduces proliferation of ERα-positive MCF7 breast cancer cells.","method":"Co-immunoprecipitation, ChIP-seq, ASXL2 knockdown with proliferation and xenograft assays, PHD finger binding assay","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 2 — reciprocal co-IP, ChIP-seq, PHD finger binding demonstrated, KD with in vivo xenograft readout; multiple orthogonal methods","pmids":["26640146"],"is_preprint":false},{"year":2009,"finding":"Loss of Asxl2 in mice reduces trimethylation of histone H3 lysine 27 (H3K27me3) in heart tissue, consistent with a role in promoting Polycomb activity. Asxl2-/- mice show both anterior and posterior axial skeleton transformations, indicating dual roles in PcG and trxG function.","method":"Gene-trap knockout mouse (Asxl2-/-), histone modification analysis (H3K27me3), skeletal phenotype analysis","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 2 — knockout mouse with direct histone modification measurement and skeletal transformation phenotype; replicated across multiple tissues","pmids":["19270745"],"is_preprint":false},{"year":2012,"finding":"Asxl2 is required for long-term maintenance of ventricular function and repression of β-MHC in adult mouse hearts. Asxl2 and the histone methyltransferase Ezh2 co-localize to the β-MHC promoter, suggesting Asxl2 directly recruits Ezh2 to repress β-MHC expression.","method":"Asxl2-/- mouse cardiac function analysis (echocardiography), chromatin immunoprecipitation (ChIP) at β-MHC promoter, myofibril protein expression analysis","journal":"Journal of molecular and cellular cardiology","confidence":"Medium","confidence_rationale":"Tier 2 — KO mouse with defined functional phenotype and ChIP evidence for Asxl2/Ezh2 co-occupancy at β-MHC promoter; single lab","pmids":["23046516"],"is_preprint":false},{"year":2011,"finding":"Asxl2 is required for osteoclastogenesis; knockdown of Asxl2 in bone marrow macrophages impairs their ability to form osteoclasts, and Asxl2 knockout mice have reduced bone mineral density.","method":"siRNA knockdown in bone marrow macrophages with osteoclast differentiation assay, Asxl2 knockout mouse with bone mineral density measurement, co-expression network analysis","journal":"PLoS genetics","confidence":"High","confidence_rationale":"Tier 2 — both KO mouse and cell-based knockdown assay showing osteoclast differentiation defect; replicated by subsequent ASXL2-/- mouse studies","pmids":["21490954"],"is_preprint":false},{"year":2017,"finding":"Asxl2 is required for normal haematopoietic stem cell self-renewal (distinct from ASXL1) and acts as a haploinsufficient tumor suppressor. Asxl2 loss promotes AML1-ETO leukemogenesis by increasing chromatin accessibility at putative enhancers of key leukemogenic loci. ASXL2 target genes strongly overlap with RUNX1 and AML1-ETO target genes.","method":"Asxl2 conditional knockout mouse, bone marrow transplantation, ATAC-seq for chromatin accessibility, ChIP analysis, leukemogenesis assays with AML1-ETO","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 — KO mouse with functional HSC assays, leukemogenesis model, ATAC-seq chromatin analysis, multiple orthogonal methods","pmids":["28516957"],"is_preprint":false},{"year":2017,"finding":"Deletion of Asxl2 in mice leads to MDS-like disease. Asxl2 loss enhances HSC self-renewal (shown by paired daughter cell assays), alters expression of genes critical for HSC self-renewal, differentiation, and apoptosis, associated with dysregulated H3K27ac and H3K4me1/2 histone marks.","method":"Asxl2 knockout mouse, bone marrow transplantation, paired daughter cell assays, histone modification analysis (H3K27ac, H3K4me1/2), gene expression profiling","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 — KO mouse with mechanistic histone mark analysis, paired daughter cell clonal assay, transplantation, multiple orthogonal approaches","pmids":["28593990"],"is_preprint":false},{"year":2013,"finding":"ASXL2 increases LXRα transcriptional activity through direct interaction in the presence of ligand, and is recruited to the ABCA1 promoter in a ligand-dependent manner. ASXL2 knockdown inhibits lipid accumulation in H4IIE cells, in contrast to ASXL1 which suppresses LXRα activity.","method":"Luciferase reporter assay, co-immunoprecipitation, chromatin immunoprecipitation (ChIP) at ABCA1 promoter, siRNA knockdown with lipid accumulation assay","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 — co-IP, ChIP, functional knockdown assay; single lab but multiple orthogonal methods","pmids":["24321552"],"is_preprint":false},{"year":2014,"finding":"ASXL2 directly interacts with the LIM domain-containing protein WTIP. ASXL2 enhances retinoic acid-dependent transcription, while WTIP represses it by blocking ASXL2's stimulatory effect. Both proteins are expressed in mouse embryonic epicardial cells regulated by retinoic acid signaling.","method":"Co-immunoprecipitation, yeast two-hybrid (genetic assay), luciferase reporter assay (retinoic acid-dependent), immunofluorescence in epicardial cells","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 3 — co-IP and reporter assay, single lab, moderate mechanistic follow-up","pmids":["25065743"],"is_preprint":false},{"year":2020,"finding":"Myeloid-specific deletion of Asxl2 prevents diet-induced obesity and adipose tissue macrophage infiltration. ASXL2 in macrophages controls energy expenditure by regulating catecholamine degradation; Asxl2ΔLysM mice have relatively increased catecholamines due to suppressed degradation by macrophages, protecting brown adipose tissue metabolism.","method":"Myeloid-specific conditional knockout (LysM-Cre), metabolic phenotyping (energy expenditure, food intake, fecal fat), nanoparticle-based siRNA delivery in vivo, cytokine/gene expression analysis","journal":"The Journal of clinical investigation","confidence":"High","confidence_rationale":"Tier 2 — tissue-specific KO with metabolic phenotyping, independent in vivo siRNA validation, multiple mechanistic readouts","pmids":["32310225"],"is_preprint":false},{"year":2026,"finding":"ASXL2 regulates EZH2 binding to the CEP162 promoter (at the 3482-3511 bp region). Hypoxia-induced downregulation of ASXL2 reduces EZH2 occupancy at the CEP162 promoter, decreasing H3K27me3 modification and increasing CEP162 transcription, which destabilizes axonemal microtubules during spermatogenesis.","method":"ASXL2 knockdown/overexpression in spermatocytes, ChIP assay at CEP162 promoter, co-immunoprecipitation (ASXL2-EZH2), protein interaction assay (CEP162-TUBB3-TUBA3A), spermatid morphology analysis","journal":"Advanced science","confidence":"Medium","confidence_rationale":"Tier 2 — ChIP at specific promoter region, co-IP, mechanistic pathway defined; single lab but multiple orthogonal methods","pmids":["41782374"],"is_preprint":false},{"year":2025,"finding":"ASXL2 knockdown in human periodontal ligament stem cells impairs osteogenic differentiation, associated with decreased activating H3K4me3 and increased repressive H2AK119ub and H3K27me3 at osteogenic gene loci.","method":"Lentiviral-mediated ASXL2 knockdown, ALP activity assay, Alizarin Red mineralization, Western blot and qPCR for osteogenic markers, global histone modification analysis","journal":"International dental journal","confidence":"Medium","confidence_rationale":"Tier 2-3 — KD with defined differentiation phenotype and histone modification readouts; single lab","pmids":["40680514"],"is_preprint":false}],"current_model":"ASXL2 is an epigenetic scaffold protein that forms a mutually exclusive complex with BAP1 (via its ASXM domain) to promote H2A K119 deubiquitination through a composite ubiquitin-binding interface, recruits MLL3/COMPASS to enhancers of tumor suppressor genes (an interaction negatively regulated by CARM1-mediated methylation at R639/R641), interacts with nuclear receptors (PPARγ, ERα, LXRα) and chromatin modifiers (EZH2, LSD1, UTX, MLL2) to regulate lineage-specific gene expression, and is required for haematopoietic stem cell self-renewal, osteoclastogenesis, cardiac function, and metabolic homeostasis, with its loss leading to dysregulation of H3K27me3, H3K4me3, and H2AK119ub chromatin marks at target loci."},"narrative":{"teleology":[{"year":2009,"claim":"The first in vivo evidence that ASXL2 has dual Polycomb/Trithorax functions came from knockout mice showing reduced H3K27me3 and bidirectional homeotic transformations, establishing ASXL2 as a chromatin regulator rather than a purely Polycomb group factor.","evidence":"Gene-trap Asxl2−/− mouse with histone modification analysis and skeletal phenotyping","pmids":["19270745"],"confidence":"High","gaps":["No biochemical mechanism for H3K27me3 regulation defined","Chromatin modifier partners not yet identified","Tissue-specific versus global role unclear"]},{"year":2011,"claim":"ASXL2 was shown to be required for osteoclastogenesis, extending its physiological roles beyond axial patterning to bone remodeling.","evidence":"siRNA knockdown in bone marrow macrophages and Asxl2 knockout mouse with bone mineral density measurement","pmids":["21490954"],"confidence":"High","gaps":["Downstream chromatin targets in osteoclasts not mapped","Mechanism linking ASXL2 to osteoclast transcriptional programs unknown"]},{"year":2012,"claim":"The cardiac requirement for ASXL2 was established and linked to EZH2 co-occupancy at the β-MHC promoter, providing the first evidence that ASXL2 directly recruits a Polycomb methyltransferase to a specific locus.","evidence":"Asxl2−/− mouse echocardiography and ChIP at β-MHC promoter","pmids":["23046516"],"confidence":"Medium","gaps":["Direct physical interaction between ASXL2 and EZH2 not demonstrated at this stage","Whether ASXL2 recruits the entire PRC2 complex or only EZH2 is unresolved","Single promoter examined"]},{"year":2013,"claim":"ASXL2 was found to coactivate LXRα-dependent transcription in a ligand-dependent manner, revealing a nuclear receptor coregulator function opposing ASXL1.","evidence":"Co-immunoprecipitation, ChIP at ABCA1 promoter, siRNA knockdown with lipid accumulation assay","pmids":["24321552"],"confidence":"Medium","gaps":["Mechanism of transcriptional activation at LXRα targets (histone marks, cofactor recruitment) not defined","In vivo metabolic significance not tested"]},{"year":2015,"claim":"The molecular basis of ASXL2-BAP1 deubiquitinase activity was resolved: ASXL2's ASXM domain binds the BAP1 CTD to form a composite ubiquitin-binding interface essential for H2AK119 deubiquitination, and BAP1 reciprocally stabilizes ASXL2 protein—establishing the core enzymatic mechanism and explaining why BAP1 cancer mutations destabilize ASXL2.","evidence":"Reconstituted in vitro DUB assays, reciprocal co-IP, active-site and domain mutagenesis including cancer-associated mutations, senescence assays","pmids":["26416890"],"confidence":"High","gaps":["Structural resolution of the CUBI interface lacking","How BAP1-ASXL2 versus BAP1-ASXL1 complexes achieve target specificity unknown"]},{"year":2015,"claim":"ASXL2 was simultaneously shown to interact with PPARγ to drive osteoclast differentiation through two genetically separable pathways (PPARγ/c-Fos for formation; PGC-1β for mitochondrial biogenesis), and with ERα plus histone modifiers (LSD1, UTX, MLL2) at estrogen-responsive promoters via its H3K4me2-binding PHD finger—defining ASXL2 as a versatile nuclear receptor coregulator and reader of histone methylation.","evidence":"ASXL2−/− mice with osteoclast assays and genetic epistasis; co-IP with ERα/LSD1/UTX/MLL2, ChIP-seq, PHD finger binding assay, MCF7 xenografts","pmids":["26051940","26640146"],"confidence":"High","gaps":["Whether PHD finger reading of H3K4me2 is required for all ASXL2 genomic occupancy untested","Structural basis of ERα versus PPARγ selectivity unknown"]},{"year":2017,"claim":"Two independent studies demonstrated that ASXL2 loss enhances hematopoietic stem cell self-renewal and promotes myeloid malignancy (AML with AML1-ETO; MDS), acting as a haploinsufficient tumor suppressor that restricts chromatin accessibility at leukemogenic enhancers and maintains proper H3K27ac/H3K4me1-2 balance.","evidence":"Conditional Asxl2 knockout mice, bone marrow transplantation, ATAC-seq, paired daughter cell assays, histone modification profiling","pmids":["28516957","28593990"],"confidence":"High","gaps":["Direct mechanistic link between BAP1-ASXL2 DUB activity and chromatin accessibility changes not established","Whether ASXL2's tumor-suppressor function requires MLL3 recruitment or only BAP1-dependent H2A deubiquitination is unclear"]},{"year":2020,"claim":"A macrophage-intrinsic metabolic role for ASXL2 was uncovered: myeloid-specific deletion protects against diet-induced obesity by suppressing catecholamine degradation, thereby preserving brown adipose tissue thermogenesis.","evidence":"Myeloid-specific conditional knockout (LysM-Cre), metabolic phenotyping, in vivo nanoparticle siRNA validation","pmids":["32310225"],"confidence":"High","gaps":["Chromatin targets in macrophages that control catecholamine degradation genes not mapped","Whether this metabolic role depends on BAP1 complex activity unknown"]},{"year":2022,"claim":"The BAP1-ASXL2 complex was shown to directly recruit MLL3/COMPASS to enhancers of tumor suppressor genes, and CARM1-mediated methylation of ASXL2 at R639/R641 was identified as a regulatory switch that disrupts this interaction—linking arginine methylation to epigenetic enhancer programming.","evidence":"Co-IP, ChIP-seq, ASXL2 KO, in vitro methylation assay, site-directed mutagenesis","pmids":["36197977"],"confidence":"High","gaps":["Whether CARM1-dependent regulation occurs at all ASXL2-dependent enhancers or a subset is unknown","No structural detail on how methylation blocks MLL3 binding"]},{"year":2025,"claim":"ASXL2 was shown to promote osteogenic differentiation of human periodontal ligament stem cells by maintaining activating H3K4me3 and reducing repressive H2AK119ub/H3K27me3 at osteogenic loci, extending its bone-regulatory role to human mesenchymal stem cell contexts.","evidence":"Lentiviral ASXL2 knockdown with ALP activity, mineralization assays, histone modification analysis","pmids":["40680514"],"confidence":"Medium","gaps":["Specific genomic loci affected not mapped by ChIP-seq","Whether BAP1 complex mediates the H2AK119ub changes in this context not tested"]},{"year":2026,"claim":"ASXL2 was linked to spermatogenesis: it recruits EZH2 to the CEP162 promoter to deposit H3K27me3 and repress CEP162 transcription, with hypoxia-induced ASXL2 loss leading to axonemal microtubule destabilization in spermatids.","evidence":"ASXL2 knockdown/overexpression in spermatocytes, ChIP at CEP162 promoter, co-IP of ASXL2-EZH2","pmids":["41782374"],"confidence":"Medium","gaps":["Genome-wide EZH2 targets dependent on ASXL2 in germ cells not mapped","Whether BAP1 is involved in this germline function unknown","Single target gene examined"]},{"year":null,"claim":"Key unresolved questions include how target specificity between BAP1-ASXL1 and BAP1-ASXL2 complexes is achieved genome-wide, whether ASXL2's tumor-suppressor function depends primarily on BAP1-mediated H2A deubiquitination or MLL3 recruitment, and how CARM1-dependent regulation integrates with nuclear receptor coactivation.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural model of the full-length ASXL2 protein or its complexes","Genome-wide discrimination between BAP1-ASXL1 and BAP1-ASXL2 targets not mapped in most tissues","Whether ASXL2's metabolic, cardiac, and germline functions are BAP1-dependent remains untested"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,1,5,12]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[3,9,10]},{"term_id":"GO:0042393","term_label":"histone binding","supporting_discovery_ids":[3,4,8]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0,1,3,5,9,12]},{"term_id":"GO:0000228","term_label":"nuclear chromosome","supporting_discovery_ids":[1,3,5,8,12]}],"pathway":[{"term_id":"R-HSA-4839726","term_label":"Chromatin organization","supporting_discovery_ids":[0,1,4,5,8,12,13]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[1,3,9,10]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[7,8]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[2,4,6,13]}],"complexes":["BAP1-ASXL2 (PR-DUB)","BAP1-ASXL2-MLL3/COMPASS"],"partners":["BAP1","EZH2","MLL3","ESR1","PPARG","LSD1","UTX","NR1H3"],"other_free_text":[]},"mechanistic_narrative":"ASXL2 is an epigenetic scaffold protein that integrates Polycomb and Trithorax group functions to regulate lineage-specific gene expression across hematopoietic, skeletal, cardiac, metabolic, and germline contexts. ASXL2 forms a mutually exclusive deubiquitinase complex with BAP1 via its ASXM domain, generating a composite ubiquitin-binding interface that promotes H2A Lys-119 deubiquitination, and independently recruits MLL3/COMPASS to enhancers of tumor suppressor genes—an interaction negatively regulated by CARM1-mediated methylation at R639/R641 [PMID:26416890, PMID:36197977]. Through its PHD finger, which preferentially binds dimethylated H3K4, ASXL2 also interacts with nuclear receptors (ERα, PPARγ, LXRα) and chromatin modifiers (EZH2, LSD1, UTX, MLL2) to coordinate activating and repressive histone marks at target promoters and enhancers [PMID:26640146, PMID:26051940, PMID:23046516]. Loss of ASXL2 in mice causes haploinsufficient tumor-suppressor defects including enhanced AML1-ETO leukemogenesis and MDS-like disease through increased chromatin accessibility at leukemogenic loci, osteopetrosis via failed osteoclast differentiation, dilated cardiomyopathy with derepression of β-MHC, and resistance to diet-induced obesity through macrophage-intrinsic regulation of catecholamine degradation [PMID:28516957, PMID:28593990, PMID:19270745, PMID:32310225]."},"prefetch_data":{"uniprot":{"accession":"Q76L83","full_name":"Putative Polycomb group protein ASXL2","aliases":["Additional sex combs-like protein 2"],"length_aa":1435,"mass_kda":153.8,"function":"Putative Polycomb group (PcG) protein. PcG proteins act by forming multiprotein complexes, which are required to maintain the transcriptionally repressive state of homeotic genes throughout development. PcG proteins are not required to initiate repression, but to maintain it during later stages of development. They probably act via methylation of histones, rendering chromatin heritably changed in its expressibility (By similarity). Involved in transcriptional regulation mediated by ligand-bound nuclear hormone receptors, such as peroxisome proliferator-activated receptor gamma (PPARG). Acts as coactivator for PPARG and enhances its adipocyte differentiation-inducing activity; the function seems to involve differential recruitment of acetylated and methylated histone H3. Non-catalytic component of the PR-DUB complex, a complex that specifically mediates deubiquitination of histone H2A monoubiquitinated at 'Lys-119' (H2AK119ub1) (PubMed:30664650, PubMed:36180891). The PR-DUB complex is an epigenetic regulator of gene expression and acts as a transcriptional coactivator, affecting genes involved in development, cell communication, signaling, cell proliferation and cell viability (PubMed:30664650, PubMed:36180891). ASXL1, ASXL2 and ASXL3 function redundantly in the PR-DUB complex (By similarity) (PubMed:30664650). The ASXL proteins are essential for chromatin recruitment and transcriptional activation of associated genes (By similarity). ASXL1 and ASXL2 are important for BAP1 protein stability (PubMed:30664650)","subcellular_location":"Nucleus","url":"https://www.uniprot.org/uniprotkb/Q76L83/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ASXL2","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":77,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/ASXL2","total_profiled":1310},"omim":[{"mim_id":"617190","title":"SHASHI-PENA SYNDROME; SHAPNS","url":"https://www.omim.org/entry/617190"},{"mim_id":"615115","title":"ASXL TRANSCRIPTIONAL REGULATOR 3; ASXL3","url":"https://www.omim.org/entry/615115"},{"mim_id":"612991","title":"ASXL TRANSCRIPTIONAL REGULATOR 2; ASXL2","url":"https://www.omim.org/entry/612991"},{"mim_id":"612990","title":"ASXL TRANSCRIPTIONAL REGULATOR 1; ASXL1","url":"https://www.omim.org/entry/612990"},{"mim_id":"603089","title":"BRCA1-ASSOCIATED PROTEIN 1; BAP1","url":"https://www.omim.org/entry/603089"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Nucleoplasm","reliability":"Enhanced"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/ASXL2"},"hgnc":{"alias_symbol":["ASXH2","FLJ10898","KIAA1685"],"prev_symbol":[]},"alphafold":{"accession":"Q76L83","domains":[{"cath_id":"-","chopping":"269-369","consensus_level":"medium","plddt":82.2413,"start":269,"end":369},{"cath_id":"-","chopping":"1407-1435","consensus_level":"medium","plddt":64.3214,"start":1407,"end":1435},{"cath_id":"1.10.10","chopping":"11-87","consensus_level":"medium","plddt":76.1365,"start":11,"end":87}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q76L83","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q76L83-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q76L83-F1-predicted_aligned_error_v6.png","plddt_mean":46.72},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ASXL2","jax_strain_url":"https://www.jax.org/strain/search?query=ASXL2"},"sequence":{"accession":"Q76L83","fasta_url":"https://rest.uniprot.org/uniprotkb/Q76L83.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q76L83/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q76L83"}},"corpus_meta":[{"pmid":"26416890","id":"PMC_26416890","title":"The BAP1/ASXL2 Histone H2A Deubiquitinase Complex Regulates Cell Proliferation and Is Disrupted in Cancer.","date":"2015","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/26416890","citation_count":113,"is_preprint":false},{"pmid":"21490954","id":"PMC_21490954","title":"Mouse genome-wide association and systems genetics identify Asxl2 as a regulator of bone mineral density and osteoclastogenesis.","date":"2011","source":"PLoS genetics","url":"https://pubmed.ncbi.nlm.nih.gov/21490954","citation_count":97,"is_preprint":false},{"pmid":"24973361","id":"PMC_24973361","title":"Frequent ASXL2 mutations in acute myeloid leukemia patients with t(8;21)/RUNX1-RUNX1T1 chromosomal translocations.","date":"2014","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/24973361","citation_count":94,"is_preprint":false},{"pmid":"12888926","id":"PMC_12888926","title":"Identification and characterization of ASXL2 gene in silico.","date":"2003","source":"International journal of oncology","url":"https://pubmed.ncbi.nlm.nih.gov/12888926","citation_count":90,"is_preprint":false},{"pmid":"26051940","id":"PMC_26051940","title":"ASXL2 Regulates Glucose, Lipid, and Skeletal Homeostasis.","date":"2015","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/26051940","citation_count":61,"is_preprint":false},{"pmid":"19270745","id":"PMC_19270745","title":"Functional conservation of Asxl2, a murine homolog for the Drosophila enhancer of trithorax and polycomb group gene Asx.","date":"2009","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/19270745","citation_count":60,"is_preprint":false},{"pmid":"28516957","id":"PMC_28516957","title":"ASXL2 is essential for haematopoiesis and acts as a haploinsufficient tumour suppressor in leukemia.","date":"2017","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/28516957","citation_count":58,"is_preprint":false},{"pmid":"25835095","id":"PMC_25835095","title":"Functional proteomics of the epigenetic regulators ASXL1, ASXL2 and ASXL3: a convergence of proteomics and epigenetics for translational medicine.","date":"2015","source":"Expert review of proteomics","url":"https://pubmed.ncbi.nlm.nih.gov/25835095","citation_count":51,"is_preprint":false},{"pmid":"26640146","id":"PMC_26640146","title":"ASXL2 promotes proliferation of breast cancer cells by linking ERα to histone methylation.","date":"2015","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/26640146","citation_count":44,"is_preprint":false},{"pmid":"28593990","id":"PMC_28593990","title":"Loss of Asxl2 leads to myeloid malignancies in mice.","date":"2017","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/28593990","citation_count":27,"is_preprint":false},{"pmid":"23046516","id":"PMC_23046516","title":"Maintenance of adult cardiac function requires the chromatin factor Asxl2.","date":"2012","source":"Journal of molecular and cellular 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medicine","url":"https://pubmed.ncbi.nlm.nih.gov/33155659","citation_count":8,"is_preprint":false},{"pmid":"35716351","id":"PMC_35716351","title":"Prepubertal onset of type 2 diabetes in Shashi-Pena syndrome due to ASXL2 mutation.","date":"2022","source":"American journal of medical genetics. 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BAP1 is essential for maintaining ASXL2 protein stability (but not ASXL1), and cancer-associated loss of BAP1 results in ASXL2 destabilization. The ASXM-CTD interaction generates a composite ubiquitin-binding interface (CUBI) that engages multiple contacts with ubiquitin to promote H2A Lys-119 deubiquitination. BAP1/ASXL2 interaction also regulates cell senescence.\",\n      \"method\": \"Co-immunoprecipitation, in vitro deubiquitination assays, active-site and domain mutagenesis (including cancer-associated mutations), cell proliferation and senescence assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — reconstituted DUB activity in vitro, reciprocal co-IP, domain mutagenesis, multiple orthogonal functional assays\",\n      \"pmids\": [\"26416890\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"ASXL2 (as a subunit of the BAP1 complex) mediates a direct interaction with MLL3/COMPASS, recruiting it to enhancers of tumor suppressor genes. ASXL2 loss results in decreased MLL3 occupancy at enhancers and reduced BAP1-MLL3 target gene expression. PRMT4/CARM1 methylates ASXL2 at R639/R641, which blocks ASXL2 binding to MLL3 and impairs MLL3/COMPASS-dependent gene expression.\",\n      \"method\": \"Co-immunoprecipitation, ChIP-seq, loss-of-function (ASXL2 knockdown/knockout), in vitro methylation assay, site-directed mutagenesis of methylation sites\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — direct interaction demonstrated by co-IP, PTM writer identified with mutagenesis, ChIP-seq for genomic occupancy, multiple orthogonal methods\",\n      \"pmids\": [\"36197977\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"ASXL2 interacts with PPARγ and regulates osteoclast differentiation via two distinct pathways: (1) a PPARγ/c-Fos-dependent pathway for osteoclast formation, and (2) a PGC-1β-dependent but c-Fos-independent pathway for osteoclast mitochondrial biogenesis. ASXL2-/- mice are insulin resistant, lipodystrophic, and severely osteopetrotic due to failed osteoclast differentiation.\",\n      \"method\": \"Genetic knockout mouse model (ASXL2-/-), genetic epistasis (c-Fos, PGC-1β pathway analysis), co-immunoprecipitation with PPARγ, osteoclast differentiation assays\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — knockout mouse with defined phenotypic readouts, genetic epistasis placing ASXL2 in PPARγ/c-Fos and PGC-1β pathways, co-IP for PPARγ interaction\",\n      \"pmids\": [\"26051940\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"ASXL2 interacts with ligand-bound ERα and forms a complex with histone methylation modifiers LSD1, UTX, and MLL2, which are recruited to E2-responsive gene promoters via ASXL2. The PHD finger of ASXL2 preferentially binds dimethylated H3K4. ASXL2 depletion reduces proliferation of ERα-positive MCF7 breast cancer cells.\",\n      \"method\": \"Co-immunoprecipitation, ChIP-seq, ASXL2 knockdown with proliferation and xenograft assays, PHD finger binding assay\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal co-IP, ChIP-seq, PHD finger binding demonstrated, KD with in vivo xenograft readout; multiple orthogonal methods\",\n      \"pmids\": [\"26640146\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Loss of Asxl2 in mice reduces trimethylation of histone H3 lysine 27 (H3K27me3) in heart tissue, consistent with a role in promoting Polycomb activity. Asxl2-/- mice show both anterior and posterior axial skeleton transformations, indicating dual roles in PcG and trxG function.\",\n      \"method\": \"Gene-trap knockout mouse (Asxl2-/-), histone modification analysis (H3K27me3), skeletal phenotype analysis\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — knockout mouse with direct histone modification measurement and skeletal transformation phenotype; replicated across multiple tissues\",\n      \"pmids\": [\"19270745\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Asxl2 is required for long-term maintenance of ventricular function and repression of β-MHC in adult mouse hearts. Asxl2 and the histone methyltransferase Ezh2 co-localize to the β-MHC promoter, suggesting Asxl2 directly recruits Ezh2 to repress β-MHC expression.\",\n      \"method\": \"Asxl2-/- mouse cardiac function analysis (echocardiography), chromatin immunoprecipitation (ChIP) at β-MHC promoter, myofibril protein expression analysis\",\n      \"journal\": \"Journal of molecular and cellular cardiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — KO mouse with defined functional phenotype and ChIP evidence for Asxl2/Ezh2 co-occupancy at β-MHC promoter; single lab\",\n      \"pmids\": [\"23046516\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Asxl2 is required for osteoclastogenesis; knockdown of Asxl2 in bone marrow macrophages impairs their ability to form osteoclasts, and Asxl2 knockout mice have reduced bone mineral density.\",\n      \"method\": \"siRNA knockdown in bone marrow macrophages with osteoclast differentiation assay, Asxl2 knockout mouse with bone mineral density measurement, co-expression network analysis\",\n      \"journal\": \"PLoS genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — both KO mouse and cell-based knockdown assay showing osteoclast differentiation defect; replicated by subsequent ASXL2-/- mouse studies\",\n      \"pmids\": [\"21490954\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Asxl2 is required for normal haematopoietic stem cell self-renewal (distinct from ASXL1) and acts as a haploinsufficient tumor suppressor. Asxl2 loss promotes AML1-ETO leukemogenesis by increasing chromatin accessibility at putative enhancers of key leukemogenic loci. ASXL2 target genes strongly overlap with RUNX1 and AML1-ETO target genes.\",\n      \"method\": \"Asxl2 conditional knockout mouse, bone marrow transplantation, ATAC-seq for chromatin accessibility, ChIP analysis, leukemogenesis assays with AML1-ETO\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — KO mouse with functional HSC assays, leukemogenesis model, ATAC-seq chromatin analysis, multiple orthogonal methods\",\n      \"pmids\": [\"28516957\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Deletion of Asxl2 in mice leads to MDS-like disease. Asxl2 loss enhances HSC self-renewal (shown by paired daughter cell assays), alters expression of genes critical for HSC self-renewal, differentiation, and apoptosis, associated with dysregulated H3K27ac and H3K4me1/2 histone marks.\",\n      \"method\": \"Asxl2 knockout mouse, bone marrow transplantation, paired daughter cell assays, histone modification analysis (H3K27ac, H3K4me1/2), gene expression profiling\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — KO mouse with mechanistic histone mark analysis, paired daughter cell clonal assay, transplantation, multiple orthogonal approaches\",\n      \"pmids\": [\"28593990\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"ASXL2 increases LXRα transcriptional activity through direct interaction in the presence of ligand, and is recruited to the ABCA1 promoter in a ligand-dependent manner. ASXL2 knockdown inhibits lipid accumulation in H4IIE cells, in contrast to ASXL1 which suppresses LXRα activity.\",\n      \"method\": \"Luciferase reporter assay, co-immunoprecipitation, chromatin immunoprecipitation (ChIP) at ABCA1 promoter, siRNA knockdown with lipid accumulation assay\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — co-IP, ChIP, functional knockdown assay; single lab but multiple orthogonal methods\",\n      \"pmids\": [\"24321552\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"ASXL2 directly interacts with the LIM domain-containing protein WTIP. ASXL2 enhances retinoic acid-dependent transcription, while WTIP represses it by blocking ASXL2's stimulatory effect. Both proteins are expressed in mouse embryonic epicardial cells regulated by retinoic acid signaling.\",\n      \"method\": \"Co-immunoprecipitation, yeast two-hybrid (genetic assay), luciferase reporter assay (retinoic acid-dependent), immunofluorescence in epicardial cells\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — co-IP and reporter assay, single lab, moderate mechanistic follow-up\",\n      \"pmids\": [\"25065743\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Myeloid-specific deletion of Asxl2 prevents diet-induced obesity and adipose tissue macrophage infiltration. ASXL2 in macrophages controls energy expenditure by regulating catecholamine degradation; Asxl2ΔLysM mice have relatively increased catecholamines due to suppressed degradation by macrophages, protecting brown adipose tissue metabolism.\",\n      \"method\": \"Myeloid-specific conditional knockout (LysM-Cre), metabolic phenotyping (energy expenditure, food intake, fecal fat), nanoparticle-based siRNA delivery in vivo, cytokine/gene expression analysis\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — tissue-specific KO with metabolic phenotyping, independent in vivo siRNA validation, multiple mechanistic readouts\",\n      \"pmids\": [\"32310225\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"ASXL2 regulates EZH2 binding to the CEP162 promoter (at the 3482-3511 bp region). Hypoxia-induced downregulation of ASXL2 reduces EZH2 occupancy at the CEP162 promoter, decreasing H3K27me3 modification and increasing CEP162 transcription, which destabilizes axonemal microtubules during spermatogenesis.\",\n      \"method\": \"ASXL2 knockdown/overexpression in spermatocytes, ChIP assay at CEP162 promoter, co-immunoprecipitation (ASXL2-EZH2), protein interaction assay (CEP162-TUBB3-TUBA3A), spermatid morphology analysis\",\n      \"journal\": \"Advanced science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP at specific promoter region, co-IP, mechanistic pathway defined; single lab but multiple orthogonal methods\",\n      \"pmids\": [\"41782374\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ASXL2 knockdown in human periodontal ligament stem cells impairs osteogenic differentiation, associated with decreased activating H3K4me3 and increased repressive H2AK119ub and H3K27me3 at osteogenic gene loci.\",\n      \"method\": \"Lentiviral-mediated ASXL2 knockdown, ALP activity assay, Alizarin Red mineralization, Western blot and qPCR for osteogenic markers, global histone modification analysis\",\n      \"journal\": \"International dental journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — KD with defined differentiation phenotype and histone modification readouts; single lab\",\n      \"pmids\": [\"40680514\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ASXL2 is an epigenetic scaffold protein that forms a mutually exclusive complex with BAP1 (via its ASXM domain) to promote H2A K119 deubiquitination through a composite ubiquitin-binding interface, recruits MLL3/COMPASS to enhancers of tumor suppressor genes (an interaction negatively regulated by CARM1-mediated methylation at R639/R641), interacts with nuclear receptors (PPARγ, ERα, LXRα) and chromatin modifiers (EZH2, LSD1, UTX, MLL2) to regulate lineage-specific gene expression, and is required for haematopoietic stem cell self-renewal, osteoclastogenesis, cardiac function, and metabolic homeostasis, with its loss leading to dysregulation of H3K27me3, H3K4me3, and H2AK119ub chromatin marks at target loci.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"ASXL2 is an epigenetic scaffold protein that integrates Polycomb and Trithorax group functions to regulate lineage-specific gene expression across hematopoietic, skeletal, cardiac, metabolic, and germline contexts. ASXL2 forms a mutually exclusive deubiquitinase complex with BAP1 via its ASXM domain, generating a composite ubiquitin-binding interface that promotes H2A Lys-119 deubiquitination, and independently recruits MLL3/COMPASS to enhancers of tumor suppressor genes—an interaction negatively regulated by CARM1-mediated methylation at R639/R641 [PMID:26416890, PMID:36197977]. Through its PHD finger, which preferentially binds dimethylated H3K4, ASXL2 also interacts with nuclear receptors (ERα, PPARγ, LXRα) and chromatin modifiers (EZH2, LSD1, UTX, MLL2) to coordinate activating and repressive histone marks at target promoters and enhancers [PMID:26640146, PMID:26051940, PMID:23046516]. Loss of ASXL2 in mice causes haploinsufficient tumor-suppressor defects including enhanced AML1-ETO leukemogenesis and MDS-like disease through increased chromatin accessibility at leukemogenic loci, osteopetrosis via failed osteoclast differentiation, dilated cardiomyopathy with derepression of β-MHC, and resistance to diet-induced obesity through macrophage-intrinsic regulation of catecholamine degradation [PMID:28516957, PMID:28593990, PMID:19270745, PMID:32310225].\",\n  \"teleology\": [\n    {\n      \"year\": 2009,\n      \"claim\": \"The first in vivo evidence that ASXL2 has dual Polycomb/Trithorax functions came from knockout mice showing reduced H3K27me3 and bidirectional homeotic transformations, establishing ASXL2 as a chromatin regulator rather than a purely Polycomb group factor.\",\n      \"evidence\": \"Gene-trap Asxl2−/− mouse with histone modification analysis and skeletal phenotyping\",\n      \"pmids\": [\"19270745\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No biochemical mechanism for H3K27me3 regulation defined\", \"Chromatin modifier partners not yet identified\", \"Tissue-specific versus global role unclear\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"ASXL2 was shown to be required for osteoclastogenesis, extending its physiological roles beyond axial patterning to bone remodeling.\",\n      \"evidence\": \"siRNA knockdown in bone marrow macrophages and Asxl2 knockout mouse with bone mineral density measurement\",\n      \"pmids\": [\"21490954\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream chromatin targets in osteoclasts not mapped\", \"Mechanism linking ASXL2 to osteoclast transcriptional programs unknown\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"The cardiac requirement for ASXL2 was established and linked to EZH2 co-occupancy at the β-MHC promoter, providing the first evidence that ASXL2 directly recruits a Polycomb methyltransferase to a specific locus.\",\n      \"evidence\": \"Asxl2−/− mouse echocardiography and ChIP at β-MHC promoter\",\n      \"pmids\": [\"23046516\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct physical interaction between ASXL2 and EZH2 not demonstrated at this stage\", \"Whether ASXL2 recruits the entire PRC2 complex or only EZH2 is unresolved\", \"Single promoter examined\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"ASXL2 was found to coactivate LXRα-dependent transcription in a ligand-dependent manner, revealing a nuclear receptor coregulator function opposing ASXL1.\",\n      \"evidence\": \"Co-immunoprecipitation, ChIP at ABCA1 promoter, siRNA knockdown with lipid accumulation assay\",\n      \"pmids\": [\"24321552\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism of transcriptional activation at LXRα targets (histone marks, cofactor recruitment) not defined\", \"In vivo metabolic significance not tested\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"The molecular basis of ASXL2-BAP1 deubiquitinase activity was resolved: ASXL2's ASXM domain binds the BAP1 CTD to form a composite ubiquitin-binding interface essential for H2AK119 deubiquitination, and BAP1 reciprocally stabilizes ASXL2 protein—establishing the core enzymatic mechanism and explaining why BAP1 cancer mutations destabilize ASXL2.\",\n      \"evidence\": \"Reconstituted in vitro DUB assays, reciprocal co-IP, active-site and domain mutagenesis including cancer-associated mutations, senescence assays\",\n      \"pmids\": [\"26416890\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural resolution of the CUBI interface lacking\", \"How BAP1-ASXL2 versus BAP1-ASXL1 complexes achieve target specificity unknown\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"ASXL2 was simultaneously shown to interact with PPARγ to drive osteoclast differentiation through two genetically separable pathways (PPARγ/c-Fos for formation; PGC-1β for mitochondrial biogenesis), and with ERα plus histone modifiers (LSD1, UTX, MLL2) at estrogen-responsive promoters via its H3K4me2-binding PHD finger—defining ASXL2 as a versatile nuclear receptor coregulator and reader of histone methylation.\",\n      \"evidence\": \"ASXL2−/− mice with osteoclast assays and genetic epistasis; co-IP with ERα/LSD1/UTX/MLL2, ChIP-seq, PHD finger binding assay, MCF7 xenografts\",\n      \"pmids\": [\"26051940\", \"26640146\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether PHD finger reading of H3K4me2 is required for all ASXL2 genomic occupancy untested\", \"Structural basis of ERα versus PPARγ selectivity unknown\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Two independent studies demonstrated that ASXL2 loss enhances hematopoietic stem cell self-renewal and promotes myeloid malignancy (AML with AML1-ETO; MDS), acting as a haploinsufficient tumor suppressor that restricts chromatin accessibility at leukemogenic enhancers and maintains proper H3K27ac/H3K4me1-2 balance.\",\n      \"evidence\": \"Conditional Asxl2 knockout mice, bone marrow transplantation, ATAC-seq, paired daughter cell assays, histone modification profiling\",\n      \"pmids\": [\"28516957\", \"28593990\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct mechanistic link between BAP1-ASXL2 DUB activity and chromatin accessibility changes not established\", \"Whether ASXL2's tumor-suppressor function requires MLL3 recruitment or only BAP1-dependent H2A deubiquitination is unclear\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"A macrophage-intrinsic metabolic role for ASXL2 was uncovered: myeloid-specific deletion protects against diet-induced obesity by suppressing catecholamine degradation, thereby preserving brown adipose tissue thermogenesis.\",\n      \"evidence\": \"Myeloid-specific conditional knockout (LysM-Cre), metabolic phenotyping, in vivo nanoparticle siRNA validation\",\n      \"pmids\": [\"32310225\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Chromatin targets in macrophages that control catecholamine degradation genes not mapped\", \"Whether this metabolic role depends on BAP1 complex activity unknown\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"The BAP1-ASXL2 complex was shown to directly recruit MLL3/COMPASS to enhancers of tumor suppressor genes, and CARM1-mediated methylation of ASXL2 at R639/R641 was identified as a regulatory switch that disrupts this interaction—linking arginine methylation to epigenetic enhancer programming.\",\n      \"evidence\": \"Co-IP, ChIP-seq, ASXL2 KO, in vitro methylation assay, site-directed mutagenesis\",\n      \"pmids\": [\"36197977\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether CARM1-dependent regulation occurs at all ASXL2-dependent enhancers or a subset is unknown\", \"No structural detail on how methylation blocks MLL3 binding\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"ASXL2 was shown to promote osteogenic differentiation of human periodontal ligament stem cells by maintaining activating H3K4me3 and reducing repressive H2AK119ub/H3K27me3 at osteogenic loci, extending its bone-regulatory role to human mesenchymal stem cell contexts.\",\n      \"evidence\": \"Lentiviral ASXL2 knockdown with ALP activity, mineralization assays, histone modification analysis\",\n      \"pmids\": [\"40680514\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Specific genomic loci affected not mapped by ChIP-seq\", \"Whether BAP1 complex mediates the H2AK119ub changes in this context not tested\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"ASXL2 was linked to spermatogenesis: it recruits EZH2 to the CEP162 promoter to deposit H3K27me3 and repress CEP162 transcription, with hypoxia-induced ASXL2 loss leading to axonemal microtubule destabilization in spermatids.\",\n      \"evidence\": \"ASXL2 knockdown/overexpression in spermatocytes, ChIP at CEP162 promoter, co-IP of ASXL2-EZH2\",\n      \"pmids\": [\"41782374\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Genome-wide EZH2 targets dependent on ASXL2 in germ cells not mapped\", \"Whether BAP1 is involved in this germline function unknown\", \"Single target gene examined\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include how target specificity between BAP1-ASXL1 and BAP1-ASXL2 complexes is achieved genome-wide, whether ASXL2's tumor-suppressor function depends primarily on BAP1-mediated H2A deubiquitination or MLL3 recruitment, and how CARM1-dependent regulation integrates with nuclear receptor coactivation.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural model of the full-length ASXL2 protein or its complexes\", \"Genome-wide discrimination between BAP1-ASXL1 and BAP1-ASXL2 targets not mapped in most tissues\", \"Whether ASXL2's metabolic, cardiac, and germline functions are BAP1-dependent remains untested\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1, 5, 12]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [3, 9, 10]},\n      {\"term_id\": \"GO:0042393\", \"supporting_discovery_ids\": [3, 4, 8]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0, 1, 3, 5, 9, 12]},\n      {\"term_id\": \"GO:0000228\", \"supporting_discovery_ids\": [1, 3, 5, 8, 12]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-4839726\", \"supporting_discovery_ids\": [0, 1, 4, 5, 8, 12, 13]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [1, 3, 9, 10]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [7, 8]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [2, 4, 6, 13]}\n    ],\n    \"complexes\": [\n      \"BAP1-ASXL2 (PR-DUB)\",\n      \"BAP1-ASXL2-MLL3/COMPASS\"\n    ],\n    \"partners\": [\n      \"BAP1\",\n      \"EZH2\",\n      \"MLL3\",\n      \"ESR1\",\n      \"PPARG\",\n      \"LSD1\",\n      \"UTX\",\n      \"NR1H3\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}